While Making out or Intense passionate kissing, your teeth connect with your partners teeth by touching, rubbing, or moving across the surface of the other persons mouth. Mostly done Accidentally, while some other more aggressive individuals do this on purpose for pleasure.

Friend 1: "Yo Bro, were you grinding teeth last night with that chick?"

Friend 2: "Yeah Bro, Of course i was when she is that easy, she was all about grinding teeth."